1. Field of the Invention
Embodiments of the invention relate to lighting, and more particularly, to a light-emitting diode shelf. Although embodiments of the invention are suitable for a wide scope of applications, it is particularly suitable for the emission of low-intensity planar light from a shelf for display lighting.
2. Discussion of the Related Art
In general, display cases are used to display wares in a commercial setting and prized possessions in a residential settings. Display cases can be open or closed. Closed display cases can have transparent doors on the front of the case, or the front of the case can be transparent and the doors are either at the side or on the back of the case. Some display cases contain shelves on which items can be positioned for display and illuminated by a lighting fixture or lighting fixtures within the display case.
Lighting fixtures for display cases use point light sources, such as incandescent bulbs, or linear light sources, such as fluorescent light tubes. Point light sources are typically shaded or directed in such way so as not to be directly in the line of sight for an individual since the high intensity of point light sources can cause discomfort. Point light sources usually emit light at a relatively high-intensity so as to be able to provide a sufficient lighting. Linear light sources can be less intense but yet emit sufficient lighting because the light emits all along the length of the linear light source. Although not as intense, linear light sources are typically diffused or shielded in such way so as not to cause discomfort. The diffusers of most linear light sources are configured to emulate a planar light source by widely diffusing a source light into a lower intensity light across a plane.
Typically, lighting schemes for display cases are implemented by using fixtures mounted in one or two of three locations within the display case. The first location is at the top of the display case so to provide light for items on the top shelf or for items on all of the shelves if the shelves are transparent. The entire case is not sufficiently lit by lighting fixtures just at the top location of the display case and items at the sides of the display case can have unflattering shadows. The second location is at the front of the display case such that the light travels toward the items on the shelf in somewhat the same direction an individual would view the item. The lighting fixtures at the front location of the display case can generate glare off of the items on display. The third location is at the back of the display case adjacent to and under each of the shelves so as to provide light high above and from behind the items on each shelf. The lighting fixtures at the back location of the display case can generate unflattering shadows for the items on display.
Lighting fixtures for display cases should provide light to items on a shelf such that a light source or light sources will provide sufficient light to the entire display case such that areas of the display case are not too bright or not too dark. Further, the light sources should not cause any discomfort in the nominal viewing directions into the display case. Furthermore, the lighting fixtures for display cases should illuminate items without glare or shadows.